[dorkbotpdx-blabber] Wire wrap - used to be "perfboard!"

[Greg Grunest]

Wire wrap is awesome for prototyping.  I've done big boards, old school
style where you've got 100+ IC's on a board and you need to check out a
design.  Anything with over 3 or 4 IC's can make sense to do in wire wrap.
It's a really good way to check your design before having boards fabricated
or just to mock something up for software development while you're waiting
for final product fabrication.  Although, don't get me wrong, it is very
permanent and I have wire-wrapped my own parallel port development tools
that have been in use since the late 80s and still work just fine.

It's pretty easy to do.  As with anything, there are numerous "right ways"
and "wrong ways" to do it and a lot of that depends on personal preference
and experience.

That said, this is generally what you need and how I do it.

You use special "wire wrap" IC sockets and then either solder the power and
ground pins onto busses to hold the socket in or hot glue them in.  I always
liked using wire wrap sockets that had a .1mf cap built in between pins 7
and 14 for TTL ICs.  It saves you having to add these later.

All discrete components such as capacitors, transistors, resistors, etc...
get soldered onto headers that fit into the wire wrap sockets.  (You *can*
just wire wrap onto the leads of the components but typically they are the
wrong size and it just looks ugly and stupid and pisses you off)


Tools: The best wire wrapping tool I ever bought was the one from radio
shack.  It goes for $6.99 and they've sold the same model since the 70's.
I've used more expensive ones including $300.00+ wire wrapping "guns" and I
just like the radio shack tool the best.  It's got a little wire stripper
made for wire-wrap wire stored in the handle.  With this tool and a pair of
wire nips, you're good to go.
http://www.radioshack.com/product/index.jsp?productId=2103243

Wire:  Get at least 3 different colors and use one for bus lines, one for
power / gnd connections, etc.., or you'll hate trying to trace wires and
track down errors once it's all wrapped.  Plus it makes it look pretty.
Ooohh... Aaahh... Norvac has bigger spools for cheaper too.  I think radio
shack used to sell a package of three different colors for like $7.00.  Well
worth it.   http://www.radioshack.com/product/index.jsp?productId=2062640 

Sockets:  Radio shack used to sell them.  Sometimes you can find them there.
Norvac and other specialty electronics places usually carry a decent
selection.
http://www.goldmine-elec-products.com/prodinfo.asp?number=G16987&variation=


So basically for around $20 you can get started in wire wrapping.  It's
worth trying.  It's much more permanent than using a protoboard and a whole
lot cheaper than having boards etched.  I think it's a whole lot easier to
change and muck with than soldered leads and jumper wires.  But it's
definitely more fragile. (The long pins tend to bend over and touch one
another if you aren't reasonably gently with it.  Build your project with
standoffs and mount it on a base to protect the pins and it will last for
years.)

Oh, one more thing... It TOTALLY SUCKS for trying to deal with any surface
mount parts.  PERIOD!  P.E.R.I.O.D!!!!  You can do it, but it sucks and you
either end up rigging up something yourself that's fragile and therefore
breaks and is *LAME* or you buy premade soic or plcc wire wrap sockets that
cost a fortune (I've paid up to $80.00 for certain types).

- Greg




-----Original Message-----
From: dorkbotpdx-blabber-bounces at dorkbot.org
[mailto:dorkbotpdx-blabber-bounces at dorkbot.org] On Behalf Of Mykle Hansen
Sent: Tuesday, May 19, 2009 11:23 AM
To: A discussion list for dorkbot-pdx (portland, or)
Subject: Re: [dorkbotpdx-blabber] perfboard!


On May 19, 2009, at 11:15 AMTuesday, Greg Grunest wrote:

> They also have some bigger perfboards that are just "perfboards" for  
> wire
> wrapping use. (No solder pads)  They can be very useful sometimes  
> and they
> hot glue together easily for making "3D" stuff.

i've never done wire wrapping, tho i've seen it done.  it always
looks like a complicated loom for gem sweaters.  is it an easier way
to build a complicated circuit than soldering?  what are the start-up
costs?  you need a wire-wrapper, right?  and some pins?  what else?

i'm down with soldering, but i like to know my options.
i already found the padded perfboard at the lombard Radio Shack.

-m-

---
HELP!  A Bear is Eating Me!
http://helpabeariseatingme.com

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